Field of the Invention
The invention relates to a fan system, and more particularly to a fan system having an external rotor.
Description of the Related Art
A typical structure for a conventional fan system includes an air blade that is welded with external surface of a housing of the external rotor. However, requirements for a welding position and a welding direction of the air blade are stringent, and a high-level welding technology is needed, which cause high production cost and low production efficiency. A different structure employs a groove disposed on an outer surface of the housing, but installation of this axial flow fan is not reliable.